aspirated shields at the Climate Reference Network station

Environmental Monitoring Program

Our program is designed to understand how the environment changes over time. Long-term monitoring lets us evaluate legislation aimed at controlling pollution and climate change. We monitor temperature and precipitation, as well as variables related to air pollution, such as acid rain, air quality, and streamwater chemistry. We also measure solar radiation (including UV).

Stream Quality

Stream Quality

Our stream monitoring program is a long-term data collection program that allows us to understand local as well as regional changes in the environment feeding our stream. The program began in 1985 and is the longest continuous chemistry dataset about the quality of streamwater in our region. Our program includes monthly grab samples collected at 2 sites on the East Branch of Wappinger Creek on the Cary Institute property. The stream is a tributary to the main branch of Wappinger Creek, which flows into the Hudson River at Wappingers Falls. Stream samples are collected at the end of every month at low flow and are analyzed for a suite of constituents that are important to ecosystem function. Additionally, we collect continuous temperature, stage height and specific conductance data at 15-minute intervals at one of the 2 sites.

For access to data go to Archived Data and Data Summaries.


wappinger creek

About Our Stream

The creek as it passes through the Cary Institute property is a relatively clean, unimpaired forest stream.  It harbors reproducing populations of brown trout as well as other important native fish and is habitat for breeding birds including common merganzer and wood duck. 

About 1.6 km upstream from our monitoring site is the Village of Millbrook sewage treatment plant.  The Village of Millbrook (population 1400) and the roads in the watershed of the stream are important sources of road salt to the stream.




Stream Temperature & Flow

At a site on the stream called the Fern Glen we monitor stream height, temperature and specific conductance.  Data are logged every 15 minutes using a microcomputer called a datalogger.

Using stream height measurements and an estimate of the cross-sectional area of the stream, we can estimate the volume of water flowing in the stream.



road salt

Road Salt

Increasing salt concentrations in our streams has been a concern at the Cary Institute for many years.  Even in the relatively undeveloped watershed of the East Branch of Wappinger Creek, the salt levels have increased since 1985 when sampling began. 

Using this long-term stream chemistry dataset together with the characteristics of the watershed feeding our stream we have shown that road salt represents over 90% of the salt in our stream.  In addition, we've discovered that salt accumulates in the subsurface (soil and groundwater) or in wetlands, ponds or lakes and slowly leaks into the stream over time.  This information helps direct policy decisions about road salt use.  From this work, we've been able to recommend ways to reduce the amount of salt necessary to keep our roads ice free during the winter.  See the report Road Salt, Moving Toward the Solution for more information.


Cary Institute of Ecosystem Studies | Millbrook, New York 12545 | Tel (845) 677-5343

Privacy Policy Copyright © 2015